JP2015169815A - Actuator device, tactile display and drive method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold displacement even when a switching element is turned off, in driving an actuator device.SOLUTION: An actuator device comprises: an actuator element which displaces according to supplied current; a drive element for supplying current from a power source to the actuator element; a switching element for switching supply and stop of supply of the current from the drive element to the actuator element; and a sensor circuit for detecting a holding capacity for holding electric charge for driving the drive element and the displacement of the actuator element between the drive element and actuator element, when current supply from the drive element to the actuator element is stopped by the switching element.

Description

  The present invention relates to driving of an actuator device.

  As a current-driven actuator element, an ion conductive polymer actuator (Ionic Polymer Metal Composite, IPMC, sometimes called ICPF (Ionic Conducting Polymer Gel Film)) is known (for example, Patent Documents 1 to 3). IPMC includes a joined body in which electrodes are joined to both surfaces of an ion conductive polymer (polymer electrolyte gel). When a voltage is applied between the electrodes, cations move, and water molecules move accordingly, and one side expands and the other side contracts. That is, when a voltage is applied, the IPMC bends. IPMC has features such as flexibility, light weight, silence, and easy miniaturization. Patent Document 1 discloses an active matrix circuit using a transistor as a switching element in order to drive an IPMC.

JP 2007-79172 A Japanese Patent Laid-Open No. 4-275078 JP-A-11-206162

  Patent Document 1 discloses a so-called 1T1C type pixel circuit using IPMC as C (capacitance). In the 1T1C type pixel circuit, the actuator is driven using the charge charged in the capacitance component of the IPMC. However, the charge charged in the capacitance component of the IPMC is discharged through the resistance component of the IPMC, and the charge cannot be held. Although it is conceivable to perform the next charge (scan) before the electric charge is discharged, if the holding period between the scans is shortened, the charge period is also proportionally shortened. It will not be possible to charge a new charge. That is, it has been difficult to achieve both the maintenance of the charge charged in the capacitance component of the IPMC and the sufficient charge of the IPMC. In addition, Patent Document 1 merely discloses a circuit for driving the IPMC.

  On the other hand, the present invention provides a technique of using this actuator element as a sensor in driving a current-driven actuator element.

The present invention relates to an actuator element that is displaced in accordance with a supplied current, a drive element that supplies a current from a power source to the actuator element, and a switching element that switches between supply and stop of current from the drive element to the actuator element A holding capacitor for holding electric charge for driving the driving element when supply of current from the driving element to the actuator element is stopped by the switching element, and the driving element and the actuator element. There is provided an actuator device having a sensor circuit for detecting displacement of the actuator element.
According to this actuator device, the actuator element can also be used as a sensor.

The switching element may be switched to an on state at a predetermined cycle, and the sensor circuit may detect the displacement in a partial period obtained by time-dividing the cycle.
According to this actuator device, the function as an actuator and the function as a sensor can coexist within one cycle of driving.

The actuator device may include a control unit that controls the displacement according to a detection result of the sensor circuit.
According to this actuator device, feedback control can be performed.

The driving element may include an inverter.
According to this actuator device, the actuator element can be charged and discharged at a higher speed.

Further, the present invention includes a plurality of unit circuits including the actuator element, the driving element, the switching element, the holding capacitor, and the sensor circuit, and the plurality of unit circuits include a first direction and the first direction. May be disposed along a second direction perpendicular to the first direction.
According to this actuator device, more various information can be displayed.

Furthermore, the present invention switches an actuator element that is displaced according to a supplied current, a drive element that supplies a current from a power source to the actuator element, and a supply and stop of current from the drive element to the actuator element. A switching element, a holding capacitor that holds electric charge for driving the driving element when supply of current from the driving element to the actuator element is stopped by the switching element, and the driving element and the actuator A tactile display having a sensor circuit for detecting a displacement of the actuator element between the elements is provided.
According to this tactile display, the actuator element can also be used as a sensor.

Furthermore, the present invention includes a step in which the actuator element is displaced according to a supplied current, a step in which the driving element supplies a current from a power source to the actuator element, and a switching element from the driving element to the actuator. A step of switching between supply and stop of current to the element, and a storage capacitor, the charge for driving the drive element when supply of current from the drive element to the actuator element is stopped by the switching element And a step of detecting a displacement of the actuator element by a sensor circuit provided between the driving element and the actuator element.
According to this driving method, the actuator element can also be used as a sensor.

The figure which shows the structure of the actuator apparatus 1 which concerns on one Embodiment. 4 is a diagram illustrating a cross-sectional structure of the display unit 10. FIG. The figure explaining the principle of an IPMC actuator. FIG. 4 is a diagram showing an equivalent circuit of the pixel 13. FIG. 4 is a diagram illustrating a specific circuit example of a pixel 13. 4 is a timing chart showing the operation of the actuator device 1. The figure explaining the operation | movement as a sensor of the actuator element 101. FIG. The figure which shows another example of the switching element. FIG. 6 is a diagram showing another example of the drive element 15. FIG. 10 is a diagram showing still another example of the drive element 15. The figure which shows another example of an inverter. The figure which shows another example of an inverter. FIG. 10 is a diagram illustrating another circuit example of the pixel 13. FIG. 14 is a diagram showing still another circuit example of the pixel 13. The figure which shows the cross-section of the display part 10 which concerns on the modification 8. FIG.

1. Configuration FIG. 1 is a diagram illustrating a configuration of an actuator device 1 according to an embodiment. The actuator device 1 is used as a tactile display, for example. The tactile display refers to a device for transmitting information via the tactile sense, and more specifically, for example, a braille display. In this paper, the terms “display” and “display” are not limited to visually transmitting information, but also include the meaning of transmitting via tactile sensation. The actuator device 1 includes a display unit 10 and a drive circuit 20.

  The display unit 10 displays information. The display unit 10 includes m scanning lines 11, n data lines 12, and a plurality (m × n) of pixels 13 (an example of a unit circuit). The scanning lines 11 are provided along the X direction (an example of the first direction), and the data lines 12 are provided along the Y direction (an example of the second direction). The pixel 13 is provided at a position corresponding to the intersection of the scanning line 11 and the data line 12. That is, in this example, the pixels 13 are arranged in a matrix along the row direction and the column direction. The pixel 13 has an actuator element (details will be described later) that are displaced according to a control signal. The displacement of the actuator element stimulates the user's sense of touch and transmits information.

  FIG. 2 is a diagram illustrating a cross-sectional structure of the display unit 10. FIG. 2 shows a structure corresponding to one pixel. The display unit 10 includes an actuator element 101, a spacer 102, a stimulation member 103, a frame 104, and a protective film 105. 2A shows a state where the actuator element 101 is not displaced (reference state), and FIG. 2B shows a state where the actuator element 101 is displaced.

  The actuator element 101 is a current-driven actuator, in this example, an ion conductive polymer (Ionic Polymer Metal Composite, IPMC) actuator. The actuator element 101 has electrodes on the front surface side (upper side) and the back surface side (lower side) in the figure (both not shown). When a voltage is applied between these electrodes, the cation in the polymer electrolyte moves to the cathode side, causing a difference in swelling between the front surface and the back surface and displacement (FIG. 2 (B)).

  FIG. 3 is a diagram for explaining the principle of the IPMC actuator. The IPMC actuator includes an ion exchange membrane 501, an electrode 502, and an electrode 503. As the ion exchange membrane 501, either a cation exchange membrane or an anion exchange membrane may be used. As the cation exchange membrane, for example, a fluororesin ion exchange membrane having a sulfone group or a carboxyl group, or a polystyrene sulfonic acid membrane is used. As the electrode, for example, a noble metal such as platinum, iridium, palladium, and ruthenium, a conductive polymer, or graphite is used.

  When operating the IPMC actuator, the ion exchange membrane 501 needs to be in a water-containing state. When a voltage is applied between the electrode 502 (anode) and the electrode 503 (cathode), the cation moves to the cathode side. At this time, water molecules also move in the ion exchange membrane 501 to the cathode side as the cations move. As the water molecules move, there is a difference in moisture content between the anode side and the cathode side. At this time, the portion with a large amount of water (cathode side) expands and the portion with a small amount of water (anode side) contracts. That is, the ion exchange membrane 501 bends to the anode side.

  Here, bending of the IPMC actuator is caused by ion movement, that is, current. This is the reason for the “current drive type”. Note that if the movement of ions stops even when a voltage is applied (the current stops flowing), the difference in water content is relaxed with time due to the diffusion of water molecules. That is, the bending of the ion exchange membrane 501 is restored.

  Refer to FIG. 2 again. When the actuator element 101 is displaced, the stimulating member 103 protrudes and gives a stimulus to the tactile sense of the user. The stimulation member 103 is a member for transmitting a stimulus to the user, and has a shape for transmitting the stimulus to the user. In this example, it is hemispherical, but it may be conical or needle-shaped. The stimulation member 103 is formed of a material such as resin (for example, polyacetal (POM)).

  The frame 104 is a member for giving structural strength to the display unit 10 and is formed of a material having a required strength (for example, polyethylene terephthalate (PET)). The frame 104 has an opening at a position corresponding to the stimulation member 103. The spacer 102 is a member for adjusting the distance between the frame 104 and the actuator element 101. The protective film 105 is a member for protecting the surface of the display unit 10. When the stimulation member 103 protrudes, it is required to expand along with the protrusion of the stimulation member 103. The protective film 105 is formed of, for example, fluorine-coated silicon rubber).

  Although not shown, a pixel circuit layer is provided below the actuator element 101. The pixel circuit layer includes a substrate, a semiconductor layer, an electrode layer, an insulating layer, and a wiring layer. The pixel circuit layer is formed using, for example, a Si-based inorganic semiconductor layer. Alternatively, the pixel circuit layer may be formed using an organic semiconductor layer.

  The actuator element 101 can also function as a sensor element. That is, when the actuator element 101 is displaced, an output of voltage or current corresponding to the displacement can be obtained.

  FIG. 4 is a diagram illustrating an equivalent circuit of the pixel 13. The pixel 13 includes a switching element 14, a driving element 15, a storage capacitor 16, a sensor circuit 17, and an actuator element 101. The switching element 14 is switched between an on state (low impedance state) and an off state (high impedance state) according to the control signal Vs. When the switching element 14 is in the on state, the input and output have the same potential, and the data voltage Vd is output to the subsequent stage. When in the off state, the output of the switching element 14 is floating.

The drive element 15 supplies a current for driving to the actuator element 101. The drive element 15 is an element whose conductivity changes according to an input signal. The drive element 15 is connected to the power supply Vsup, and outputs a current corresponding to the conductivity to the actuator element 101. The current density of the current supplied from the driving element 15 to the actuator element 101 is, for example, 10 to 100 mA / cm ² .

  Note that when the switching element 14 is in the ON state, the data voltage Vd is written to the storage capacitor 16. Therefore, current is supplied to the actuator element 101 even when the switching element 14 is turned off. The discharge in the actuator element 101 uses discharge due to the resistance component of the actuator element 101.

  The sensor circuit 17 is a circuit for taking out a signal corresponding to the displacement of the actuator element 101. The sensor circuit 17 is provided between the drive element 15 and the actuator element 101.

  FIG. 5 is a diagram illustrating a specific circuit example of the pixel 13. In this example, both the switching element 14 and the driving element 15 are n-channel FETs (Field Effect Transistors, field effect transistors, which are thin films as structures and are also referred to as TFTs (Thin Film Transistors)). The control terminal (gate), input terminal (source), and output terminal (drain) of the switching element 14 are connected to the scanning line 11, the data line 12, and the control terminal (gate) of the driving element 15, respectively. The control signal of the switching element 14 is positive logic, and is turned on when a high level voltage is applied to the scanning line 11 and turned off when a low level voltage is applied.

  Also for the driving element 15, the input signal is positive logic. That is, the higher the voltage value of the data line 12 when the switching element 14 is on, the higher the conductivity of the driving element 15 (impedance becomes lower), and the lower the voltage value, the lower the conductivity (impedance becomes higher). ). Thus, the current supplied to the actuator element 101 is determined according to the signal voltage of the data line 12.

  The sensor circuit 17 includes an FET 171 and an FET 172. The FET 171 is an n-channel FET, and the FET 172 is a p-channel FET. A control signal G is input to the gates of the FET 171 and the FET 172. The control signal G is a signal for switching the operation of the actuator element 101 as an actuator and the operation as a sensor. When the control signal G is at a high level, the FET 171 is turned on and the FET 172 is turned off. A signal is supplied from the drive element 15 to the actuator element 101. When the control signal G is at a low level, the FET 171 is turned off and the FET 172 is turned on. The actuator element 101 outputs a signal corresponding to the displacement as the detection signal Sout. That is, when the control signal G is at a high level, the actuator element 101 functions as an actuator. When the control signal G is at a low level, the actuator element 101 functions as a sensor.

  Refer to FIG. 1 again. The drive circuit 20 supplies a control signal and a data signal to the display unit 10. The drive circuit 20 includes a scanning line drive circuit 21, a data line drive circuit 22, and a control circuit 23.

  The scanning line driving circuit 21 outputs a scanning signal Y for selecting a row to which a data signal is applied from the m scanning lines 11. The scanning signal Y is, for example, a signal that sequentially becomes a high level exclusively. The data line driving circuit 22 outputs a data signal X. The data signal X is a signal having a voltage value that determines the conductivity of the drive element 15 (in other words, determining the displacement amount of the actuator element 101). The data line driving circuit 22 outputs a data signal X. The data signal X is a signal having a data voltage corresponding to the pixel 13 in the row selected by the scanning signal Y. The scanning line driving circuit 21 and the data line driving circuit 22 are controlled by the control circuit 23.

  The control circuit 23 controls the scanning line driving circuit 21 and the data line driving circuit 22 in accordance with a command output from a host device (not shown) (for example, a computer device having a CPU and a memory). The control circuit 23 includes a VRAM (Video RAM) (not shown) that stores data for one screen written to each pixel 13. The host device writes data indicating information (for example, Braille) to be displayed in the VRAM, and instructs the control circuit 23 to display the information. The control circuit 23 causes the scanning line driving circuit 21 to start scanning the scanning line 11. Further, the control circuit 23 controls the data line driving circuit 22 so that the data stored in the VRAM is written in synchronization with the scanning of the scanning line 11.

  In addition, the control circuit 23 performs processing according to the detection signal Sout. The processing corresponding to the detection signal Sout is, for example, amplification, storage of the detection signal Sout, and output to a circuit (device) at the subsequent stage.

2. Operation FIG. 6 is a timing chart showing the operation of the actuator device 1 according to the embodiment. Here, for the sake of explanation, a start signal Ps, a scanning signal Y, and a data signal X are shown. Since the operation using the actuator element 101 as a sensor will be described separately, only the operation as an actuator is shown here. Note that the jth scanning line counted from the top is called a scanning line 11 (j), and a scanning signal supplied to the scanning line 11 (j) is called a scanning signal Y (j). Similarly, the i-th data line counted from the left is called a data line 12 (i), and a data signal supplied to the data line 12 (i) is called a data signal X (i). When the start signal Ps supplied from the control circuit 23 becomes high level, the scanning line driving circuit 21 starts scanning the scanning line 11. In other words, the scanning line driving circuit 21 supplies the scanning signal Y that is sequentially set to the high level to the m scanning lines 11. The data line driving circuit 22 supplies the corresponding data signal of the selected row in synchronization with the scanning of the scanning line 11. The scanning line 11 may be scanned periodically.

  The driving method of the actuator element 101 includes digital driving and analog driving. The digital drive is a method in which the voltage applied to the actuator element is constant regardless of the displacement amount (data), and the displacement amount is controlled by the voltage application time. The analog drive is a method of controlling the displacement amount by changing the voltage applied to the actuator element according to the displacement amount (data) (the voltage application time is constant).

  According to the actuator device 1, even after the scanning of the scanning line 11 is completed and the switching element 14 is turned off, the data voltage is held by the holding capacitor 16 and current is supplied from the driving element 15. Since the actuator element is not used as a capacitor, a sufficient charge is supplied to the actuator element. Therefore, the display state of the actuator element 101 can be held for a longer time than when the holding capacitor 16 is not provided.

  FIG. 7 is a diagram for explaining the operation of the actuator element 101 as a sensor. In the actuator element 101, the operation as an actuator and the operation as a sensor are switched in a time division manner. Here, an example of digital driving is shown. For the sake of simplicity, only the operation for one pixel is shown. In this example, data is periodically written to the actuator element 101. That is, scanning of the scanning line 11 is performed periodically.

  In this example, one period is divided into a driving period and a sensing period. The drive period is a period for causing the actuator element 101 to function as an actuator, and has a certain length of time. The scanning signal Y is at a high level during the driving period and is at a low level during the sensing period. In the data signal X, the voltage level indicates either a high level or a low level, and becomes a high level for a time length corresponding to the data (displacement amount). For example, when the data indicates zero displacement, the voltage level is low during the entire driving period. On the other hand, when the data indicates the maximum displacement amount, the voltage level is high in all the driving periods. In the example of FIG. 7, the first period has a larger displacement than the second period, and the period during which the data signal X is at a high level is longer.

  The control signal G is at a high level during the driving period and is at a low level during the sensing period. FIG. 7 also shows the potential at the point A between the driving element 15 and the sensor circuit 17 and the potential at the point B between the sensor circuit 17 and the actuator element 101 in the circuit of FIG. The potential at the point A is at a high level during a period in which both the scanning signal Y and the data signal X are at a high level, and is at a low level during a period in which either one is at a low level. Further, the potential at the point A is floating during the period in which the control signal G is at a low level (shown by hatching in the figure). The potential at the point B is the same as the potential at the point A during the driving period, but becomes a potential according to the displacement of the actuator element 101 during the sensing period. The detection signal Sout is floating during the driving period, but becomes a potential corresponding to the displacement of the actuator element 101 during the sensing period.

  Thus, according to the present embodiment, the displacement state of the actuator element 101 can be detected while controlling the displacement of the actuator element 101 according to the data. For example, when the actuator device 1 is used as a braille display, it is possible to detect that the braille has been touched, that is, that the braille has been read. Alternatively, feedback control can be performed using the detection signal Sout. That is, for example, the control circuit 23 compares the displacement indicated by the detection signal Sout with the displacement indicated by the data signal X, and if the two are different, the data signal X may be corrected so that the displacement is in accordance with the data. Good.

3. Modifications The present invention is not limited to the above-described embodiments, and various modifications can be made. Hereinafter, some modifications will be described. Two or more of the following modifications may be used in combination.

3-1. Modification 1
Actuator element 101 is not limited to an IPMC actuator. Actuators other than IPCM actuators such as ion gel actuators, bucky gel actuators, and conductive polymer actuators may be used. The ion gel refers to a polymer electrolyte membrane in which an ionic liquid is confined in a polymer network structure. Bucky gel is a gelled single-walled carbon nanotube and ionic liquid. In either case, when a voltage is applied with electrodes attached to both sides of the gel film, the gel film is displaced to the positive electrode side. As the conductive polymer, for example, polyacetylene, polyaniline, polypyrrole, or polythiophene is used.

3-2. Modification 2
FIG. 8 is a diagram illustrating another example of the switching element 14. For the n-channel FET described in the embodiment, the control signal (scanning signal) is positive logic, which is suitable when a Si-based material is used for the semiconductor layer. FIG. 8A shows a p-channel FET. In this case, the control signal (scanning signal) is negative logic. The p-channel FET is suitable when an organic material is used for the semiconductor layer. FIG. 8B shows a transfer gate. Although it is necessary to use a differential signal as a control signal, the transfer gate has a feature that it can be easily transmitted regardless of whether the data voltage Vd is at a high level or a low level.

3-3. Modification 3
FIG. 9 is a diagram illustrating another example of the driving element 15. For the n-channel FET described in the embodiment, the control signal (data signal) is positive logic, which is suitable when a Si-based material is used for the semiconductor layer. FIG. 9 shows an example using a p-channel FET. In this case, the control signal (data signal) is negative logic. The p-channel FET is suitable when an organic material is used for the semiconductor layer. In FIG. 8 and the subsequent figures, the power supply voltages are generalized as Vss and Vdd. In the example of FIG. 5, Vss is a ground potential (GND), and Vdd is Vsup.

3-4. Modification 4
FIG. 10 shows an example in which an inverter is used as yet another example of the drive element 15. Various inverters can be used as specific circuits. Here, an example using a so-called CMOS inverter, that is, an n-channel FET and a p-channel FET is shown. In the circuit example of FIG. 5, the data signal is input to the gate of the driving element 15. That is, the data signal is used as a control signal for controlling on / off, and the voltage applied to the actuator element 101 when the drive element 15 is in the on state is always the power supply voltage Vsup. Therefore, the only way to reduce the displacement of the actuator element 101 (return to the reference state) is to wait for the natural discharge in the actuator element 101. On the other hand, if an inverter is used, the voltage applied to the actuator element 101 can be changed according to the data voltage Vd. For example, when Vss = GND and Vdd = Vsup, the voltage applied to the actuator element 101 can be changed in the range from zero to Vsup. That is, the actuator element 101 can be forcibly discharged (zero V applied) to quickly relax the displacement of the actuator element 101.

3-5. Modification 5
FIG. 11 is a diagram illustrating another example of the inverter. FIGS. 11A and 11B show an n-type inverter. The inverter in FIG. 11A includes an FET 151 and an FET 152. The FET 151 and the FET 152 are both n-channel FETs and are connected in series. A control signal Ctrl is input to the gate of the FET 151. A signal for turning on the FET 151 is input to the control terminal Ctrl. A data signal is input to the gate of the FET 152. In a CMOS inverter, an n-channel FET and a p-channel FET have to be formed over one substrate. In FIG. 11A, an inverter can be manufactured using only an n-channel FET.

  The inverter in FIG. 11B includes an FET 151 and an FET 152. In this example, the FET 151 is a depletion type FET, and the FET 152 is an enhancement type FET. The gate of the FET 151 is connected to the source. In FIG. 11B, an n-type inverter that operates without using a control signal can be manufactured.

  FIGS. 11C and 11D show a p-type inverter. The inverter in FIG. 11C includes an FET 153 and an FET 154. Both the FET 153 and the FET 156 are p-channel FETs and are connected in series. A control signal Ctrl is input to the gate of the FET 154. A signal for turning on the FET 154 is input to the control terminal Ctrl. A data signal is input to the gate of the FET 153. In FIG. 11C, an inverter can be manufactured using only a p-channel FET.

  The inverter in FIG. 11D includes an FET 153 and an FET 154. In this example, the FET 154 is a depletion type and the FET 153 is an enhancement type FET. The gate of the FET 154 is connected to the drain. In FIG. 11B, a p-type inverter that operates without using a control signal can be manufactured.

3-6. Modification 6
FIG. 12 is a diagram illustrating still another example of the inverter. FIG. 12 shows a so-called pseudo-CMOS inverter. 12 (A) and 12 (B) show an n-type pseudo-COMS inverter. The inverters in FIGS. 12A and 12B have four FETs, FETs 1501 to 1504. These are all n-channel FETs. The four FETs having the same gate threshold voltage can be used (the depletion type and the enhancement type do not have to coexist).

  12C and 12D show a p-type pseudo-COMS inverter. The inverters of FIGS. 12C and 12D have four FETs, FETs 1501 to 1508. These are all n-channel FETs. The four FETs having the same gate threshold voltage can be used (the depletion type and the enhancement type do not have to coexist).

3-7. Modification 7
FIG. 13 is a diagram illustrating another circuit example of the pixel 13. In this example, the drive element 15 switches the output voltage to either Vsup or GND according to the data signal. The drive element 15 includes an inverter 155, an FET 156, and an FET 157. An inverted signal of the data signal is supplied to the gate of the FET 156, and a data signal is supplied to the gate of the FET 156. When n-channel FETs are used as the FET 156 and the FET 157, the voltage supplied to the actuator element 101 is Vsup when the data voltage is high, and is zero V when the data voltage is low. .

3-8. Modification 8
FIG. 14 is a diagram illustrating still another circuit example of the pixel 13. This circuit is a modification of the circuit of FIG. Compared with the circuit of FIG. 13, in this circuit, the driving element 15 does not have the inverter 155. Further, the pixel 13 does not have the storage capacitor 16. In addition, the switching element 14 includes an FET 141 and an FET 142. Further, in addition to the data line 12, a data line 19 is provided. Complementary signals are supplied to the data lines 12 and 19. That is, an inverted signal of the data signal X of the data line 12 is supplied to the data line 19. When n-channel FETs are used as the FET 156 and the FET 157, the voltage supplied to the actuator element 101 is Vsup when the data voltage is high, and is zero V when the data voltage is low. .

  When the circuit of FIG. 14 is compared with the circuit of FIG. 13, one FET is reduced and one data line is added. Therefore, when the area of the FET is larger than the area of the data line, the area of the pixel 13 can be reduced as compared with the circuit of FIG. Alternatively, when the yield of the FET is lower than the yield of the data line, the yield of the pixel 13 can be improved as compared with the circuit of FIG.

3-9. Modification 9
FIG. 15 is a diagram showing a cross-sectional structure of the display unit 10 according to Modification 8. As shown in FIG. The cross-sectional structure of the display unit 10 is not limited to that illustrated in FIG. In the example of FIG. 2, the electrode of the actuator element 101 is oriented in a direction parallel to the display surface (FIG. 15A). That is, the direction of displacement of the actuator element 101 is a direction substantially perpendicular to the display surface. However, in the example of FIG. 13, the electrodes of the actuator element 101 are oriented in a direction perpendicular to the display surface. That is, the direction of displacement of the actuator element 101 is substantially parallel to the display surface. In this example, the direction of displacement of the actuator element 101 is determined by the polarity of the voltage applied to the actuator element 101 (the direction of the current supplied to the actuator element 101). For example, when the voltage applied to the actuator element 101 is positive, the actuator element 101 is displaced to the right (FIG. 15B), and when negative, the actuator element 101 is displaced to the left (FIG. 15C). ). In this case, for example, two power sources, a high voltage power source and a low voltage power source, are switched and used. By using the display unit having such a structure, it is possible to transmit more various information, for example, a touch feeling like a cloth.

3-10. Other Modifications The details of the sensor circuit 17 are not limited to those exemplified in the embodiment. Any circuit configuration may be used as long as a signal corresponding to the displacement can be extracted from the actuator element 101. A signal extracted from the actuator element 101 is not limited to a voltage signal, and may be a current signal.

  The actuator device 1 may have any shape. For example, the actuator device 1 may have a shape wound around a fingertip. In this case, the size of the display area of the actuator device 1 (area where the pixels 13 are present) is about 20 to 30 mm square. In this case, the display unit 10 and the drive circuit 20 may be formed separately and connected by a cable. Alternatively, the actuator device 1 may have a display area larger than that used on a desk or table.

  The actuator device 1 is not limited to that used as a braille display. Any device other than a braille display may be used as long as it transmits information via a tactile sense. Further, the actuator device 1 may be used, for example, in an information processing device having a touch screen to project positions corresponding to the keys on the screen when a keyboard user interface screen is displayed.

  The actuator device 1 is not limited to a dot matrix type display device. The actuator device 1 may be a segment type display device.

DESCRIPTION OF SYMBOLS 1 ... Actuator apparatus, 10 ... Display part, 11 ... Scan line, 12 ... Data line, 13 ... Pixel, 14 ... Switching element, 15 ... Drive element, 16 ... Retention capacity, 17 ... Sensor circuit, 20 ... Drive circuit, 21 DESCRIPTION OF SYMBOLS ... Scanning line drive circuit, 22 ... Data line drive circuit, 23 ... Control circuit, 101 ... Actuator element, 102 ... Spacer, 103 ... Stimulation member, 104 ... Frame, 105 ... Protective film, 151 ... Inverter, 152 ... FET, 153 ... FET, 154 ... inverter, 155 ... inverter, 171 ... FET, 172 ... FET, 1501-1512 ... FET

Claims (7)

An actuator element that displaces according to the supplied current;
A driving element for supplying a current from a power source to the actuator element;
A switching element that switches between supply and stop of current from the drive element to the actuator element;
When supply of current from the drive element to the actuator element is stopped by the switching element, between a holding capacitor that holds electric charge for driving the drive element and the drive element and the actuator element, A sensor circuit for detecting displacement of the actuator element;
Actuator device. The switching element is switched on in a predetermined cycle,
The actuator device according to claim 1, wherein the sensor circuit detects the displacement in a part of the period obtained by time-division. The actuator device according to claim 1, further comprising: a control unit that controls the displacement according to a detection result by the sensor circuit. The actuator device according to any one of claims 1 to 3, wherein the driving element includes an inverter. A plurality of unit circuits including the actuator element, the driving element, the switching element, the holding capacitor, and the sensor circuit;
5. The actuator device according to claim 1, wherein the plurality of unit circuits are arranged along a first direction and a second direction perpendicular to the first direction. An actuator element that displaces according to the supplied current;
A driving element for supplying a current from a power source to the actuator element;
A switching element that switches between supply and stop of current from the drive element to the actuator element;
A holding capacitor for holding a charge for driving the driving element when the switching element stops supplying current from the driving element to the actuator element;
A tactile display comprising: a sensor circuit that detects displacement of the actuator element between the driving element and the actuator element. The actuator element is displaced in response to the supplied current;
A driving element supplying a current from a power source to the actuator element;
A switching element switching between supply and stop of current from the drive element to the actuator element;
Holding a charge for driving the driving element when a supply of current from the driving element to the actuator element is stopped by the switching element;
A method for driving an actuator device, comprising: a sensor circuit provided between the drive element and the actuator element detecting a displacement of the actuator element.

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